Wild birds can be exposed to high concentrations of lead caused by spent lead shot
and industrial waste. The immunosuppressive effects of lead have been demonstrated in
laboratory mammals, but little research has been conducted in birds. Because
immunocompetence is important for survival, the effects of acute lead exposure on immune
function in 2 quail species, Japanese quail (Cotumix coturllix) and northern bobwhites
(Colinus virginianus), were investigated. In preliminary experiments, intubation with lead
shot produced inconsistent doses within treatment groups. Both quail species exhibited
poor antibody responses after immunization with sheep erythrocytes. In a third
experiment, male Japanese quail were dosed with 100 or 400 ppm lead in drinking water
for 7 days. Quail were fed either laying mash or com. Some quail were treated with
corticosterone as a positive control Lead enhanced the loss of body mass caused by com.
Lead-induced mortality was observed only in quail fed com. There was marginal evidence
that lead increased the heterophil to lymphocyte ratio in quail fed com. Com decreased the
cell-mediated immune response to an intradermal injection of phytohemagglutinin.
Corticosterone suppressed cell-mediated immunity more than lead. The primary total
antibody response to chukar (Alectoris graeca chukar) erythrocytes was significantly
suppressed in lead-dosed quail fed com. Lead also reduced the secondary total antibody
and IgG responses in the low lead/com group. The most pronounced effect of lead on
immune function was a suppression of antibody responses in groups that exhibited clinical
lead poisoning.